Method of manufacturing a semiconductor device by using a matrix frame

ABSTRACT

A method of manufacturing a semiconductor device includes providing a matrix frame which includes a plurality of die pads, mounting a semiconductor chip on the respective die pads, and sealing the semiconductor chip in blocks. After the semiconductor chip is sealed by the sealing resin, inner leads which are extended from the sealing resin are punched by a punching blade. Then, the block is diced to individual semiconductor devices by a rotary blade.

CROSS REFERENCE TO RELATED APPLICATION

A claim of priority under 35 U.S.C. §119 is made to Japanese PatentApplication No. 2003-430438, filed Dec. 25, 2003, which is hereinincorporated by reference in its entirety for all purposes.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method of manufacturing asemiconductor device which has a sealing resin.

2. Description of the Related Art

A technique of manufacturing a semiconductor device using a matrix frameis disclosed in reference 1: Japanese Patent Laid-Open No. 2000-124239.The matrix frame which is disclosed in reference 1 includes a pluralityof die pads which are arranged in a matrix. A semiconductor chip ismounted on the respective die pads. A couple of the semiconductor chipsand the die pads are grouped and sealed in groups by a sealing resin.Such technique may be called a block molding method.

A reference 2: Japanese Patent Laid-Open No. 2002-43344 discloses atechnique of manufacturing a semiconductor device using a matrix frame.The reference 2 discloses the following method. First, semiconductorchips are sealed in groups. Each of the groups includes a plurality ofthe semiconductor chips which are aligned. Then, each of the groups isseparated. Finally, the sealed group is divided and individualsemiconductor devices are obtained.

In the block molding method, only a peripheral area of the lead frame isclamped by a mold. Therefore, in a central area of the lead frame whichis not clamped by the mold, a position of an inner lead might be moved,when a molding resin is injected in the mold.

Also, in the central area of the lead frame, a flash of the resin mightbe formed at a rear surface of the lead frame. It is difficult to removethe flash, and an additional step for removing the flash is needed.

Further, when the sealed block is divided by a dicing blade, a rotaryspeed of the dicing blade is decreased for cutting a lead frame enclosedby the sealing resin. Therefore, the dividing step requires a lot oftime.

SUMMARY OF THE INVENTION

Accordingly, in one aspect of the present invention, a method ofmanufacturing a semiconductor device includes providing a matrix framewhich includes a plurality of die pads, mounting a semiconductor chip onthe respective die pads, and sealing the semiconductor chip in blocks.After the semiconductor chip is sealed by the sealing resin, inner leadswhich are extended from the sealing resin are punched by a punchingblade. Then, the block is diced to individual semiconductor devices by arotary blade.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plane view showing semiconductor devices of the presentinvention.

FIG. 2 is a cross-sectional view showing the semiconductor devices ofthe present invention.

FIG. 3(A) to FIG. 3(C) are views showing the semiconductor device of thepresent invention.

FIG. 4 is a plane view showing a matrix frame of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A method of manufacturing a semiconductor device according to preferredembodiments of the present invention will be explained hereinafter withreference to the accompanying figures. In order to simplify theexplanation, like elements are given like or corresponding referencenumerals. Dual explanations of the same elements are avoided.

Initially, a structure of a lead frame 20 of the present invention isdescribed by referring to FIG. 4. The lead frame 20 is made from a metalplate such as copper and has a rectangular configuration. The lead frame20 includes a plurality of die pads 28, a frame portion 21, supportingleads 29, connecting portions 23, and inner leads 26. Each of the partincluding the die pads 28, supporting leads 29, connecting portion 23,and inner leads 26 are formed by a punching method or by a etchingmethod from the metal plate.

The die pads 28 are arranged in a matrix with a distance providedbetween each of the die pads 28. Each of the die pads 28 has arectangular configuration. The die pad 28 has a first side 28 a and asecond side 28 b which are extended in a vertical direction, and a thirdside 28 c and a fourth side 28 d which are extended to a horizontaldirection.

The frame portion 21 is a peripheral area of the lead frame 20. That is,the frame portion 21 surrounds the die pads 28 at a distance from thedie pads 28. Sprocket holes 22 are formed in parts of the frame portion21 which are extended in a horizontal direction. The sprocket holes 22are used for moving the lead frame 20.

The supporting leads 29 are formed between the frame portion 21 and thedie pads 28 which are located near the outside of the die pads matrix.Also, the supporting leads 29 are formed between each of the die pads28. As a result, the die pads 28 which are aligned in the verticaldirection are supported between the upper side of the frame portion 21and the lower side of the frame portion 21 by the supporting leads 29.

The connecting portions 23 are connected between the upper side of theframe portion 21 and the lower side of the frame portion 21.

The inner leads are extended from the connecting portions 23 and theframe portion 21 to the first sides 28 a and the second sides 28 b ofthe die pads 28 so that tips of the inner leads face the first sides 28a and the second sides 28 b of the die pads 28. That is, the inner leadsare extended in the horizontal direction.

Supporting leads 29 are connected to the frame portion 21. In thisembodiment, the supporting leads 29 have a line configuration.

Next, a method of manufacturing the semiconductor device is described byreferring to FIG. 1 and FIG. 2.

FIG. 1 is a plane view showing semiconductor devices. FIG. 2 is across-sectional view taken along line 2-2′ in FIG. 1. In FIG. 2, a moldis described for understanding a sealing step.

A row of the die pads 28 is used for a dummy area 34. In thisembodiment, the dummy area 34 includes die pads 28 which are lined inthe horizontal direction. The dummy area 34 is arranged in a middle ofthe die pad rows.

A semiconductor chip 42 is mounted on the respective die pads 28. In thedummy area 34, the semiconductor chip 42 is not mounted on the die pads28. The semiconductor chip 42 includes a top surface 42 a which includesa plurality of electrode pads 44 and a bottom surface 42 b. Theelectrode pads 44 are arranged along the first side 28 a and the secondside 28 b of the die pad 28.

In this embodiment, five rows of the die pads 28 and four columns of thedie pads 28 are described in FIG. 1.

The semiconductor chip 42 is adhered on the die pad 28 by an insulatingadhesive material 27 as shown in FIG. 2. Also an insulating adhesivetape can be used for the insulating adhesive material 27.

Then, the electrode pads 44 are connected to the inner leads 26 bybonding wires 46 as shown in FIG. 2. The electrode pads 44 correspondone-to-one with the inner leads 26.

Then, a sealing resin 31 is formed as shown in FIG. 2. The sealing resin31 seals the semiconductor chips 42, the bonding wires 46, and the innerleads 26.

The sealing resin 31 is formed as block group 30. The block group 30includes sealing resin blocks 30 a. In this embodiment, each of thesealing resin blocks 30 a is formed at every column of the die pads 28,and includes four semiconductor chips 42.

The sealing step is performed by setting the lead frame 20 between amold 50 which includes an upper mold 50 a and an lower mold 50 b.

Cavities 52 are formed between the upper mold 50 a and the lower mold 50b. Each of the die pad columns is arranged in the respective cavities52.

Surfaces 54 a of mold portions 54 which are located between cavities 52are contacted to the connecting portion 23 and a part of the inner leads26 of the lead frame 20, when the sealing step is performed.

A surface of the lower mold 50 b is flat, and is contacted to an entirebottom surface of the lead frame 20.

After ejecting the lead frame 20 from the mold 50, a separating step isperformed. In this embodiment, the separating step includes thefollowing two steps.

A first step is a punching step by using a punching blade. A second stepis a dicing step by using a rotary blade.

First, sides of the sealing resin blocks 30 a are punched by thepunching blade. The punching step can be performed by a punching moldwhich includes a plurality of the punching blades.

A rectangular or similarly shaped punching area 25 is shown by a brokenline in FIG. 1. The punching blade has a rectangular punching surfacewhich corresponds to the punching area 25. The punching blade punchesthe connecting portion 23 and a part of the inner leads 26. Now, aminimum width of commonly used punching blade is 3 mm to 4 mm.Therefore, a width of the connecting portion 23 should be shorter than awidth of the punching blade, for punching the part of the inner leads26.

The supporting portion 23 which is located in the dummy area 34 is notpunched. That is, the punching step is performed at a first punchingarea 25 a and a second punching area 25 b which are located at bothsides of the dummy area 34. After the punching step is performed, eachof the sealing resin blocks 30 a is connected by the supporting portions23 which are located in the dummy area 34.

The rectangular punching area 25 a and the rectangular punching area 25b can be punched simultaneously by using the punching mold. Each of thepunching blades of the punching mold corresponds to the punching areas25 a and the punching areas 25 b.

Then the dicing step is performed to the punched sealing resin blocks 30a, so that the respective semiconductor devices 10 are separated. Thedicing step is performed by cutting the sealing blocks 30 a at dicinglines L1 as shown in FIG. 1.

A width of the dummy area w2 is the same as a width of the width of thenormal device area w3. As a result, the dicing step by using the rotaryblade can be performed at even intervals.

In this dicing step, the sealing resin 31 and the supporting leads 29are cut by the rotary blade. That is, the inner leads 26 are not cut bythe rotary blade. Therefore, the dicing step can be performed in a shorttime. Also, the punching step which is performed to the inner leads 26can inhibit a flash of the inner leads 26.

Next, the semiconductor device 10 which is manufactured by the method ofthis invention is described by referring to FIG. 3(A) to FIG. 3(C).

FIG. 3(A) is a schematic diagram showing the semiconductor device 10.FIG. 3(B) is a cross-sectional view taken along line 3(B)-3(B)′ in FIG.3(A). FIG. 3(C) is a bottom view showing the semiconductor device 10.

The semiconductor device 10 includes the semiconductor chip 42. Thesemiconductor chip includes the top surface 42 a and the bottom surface42 b. The electrode pads 44 are formed on the top surface 42 a.

The semiconductor chip 42 is mounted on the die pad 28 with the adhesivematerial 27.

The bottom surface of the inner leads 26 which are exposed from a bottomsurface 31 e of the semiconductor device 10 are used as externalterminals. The sealing resin 31 is remaines between the externalterminals 26 as resin portions 31 d.

The external terminals 26 are project from both of the side surfaces 31b of the semiconductor device 10. The external terminals 26 are arrangedat even intervals.

In the side surface 31 c of the semiconductor device 10, a cuttingsurface of the supporting lead 29 is exposed as shown in FIG. 3(A).

While the preferred form of the present invention has been described, itis to be understood that modifications will be apparent to those skilledin the art without departing from the spirit of the invention. The scopeof the invention is to be determined solely by the following claims.

1. A method of manufacturing a semiconductor device comprising:providing a matrix frame which includes a frame portion which isarranged in a peripheral area of the matrix frame, a plurality of diepad groups each of which includes a plurality of die pads and a dummypad which are arranged along a line, supporting leads which support thedie pads, connecting portions which are arranged between respective diepad groups, and inner leads which are connected to the connectingportions; mounting semiconductor chips on the die pads, the dummy padshaving no semiconductor chips mounted thereon; sealing the die pads, thedummy pads, the semiconductor chips, the inner leads, and the supportingleads by a sealing resin; punching the connecting portions and the innerleads which are arranged between the die pads with a punching blade,wherein the inner leads and the connecting portions which are arrangedbetween the respective dummy pads are not punched; and dicing thesupporting leads and the resin between the respective die pads with arotary blade.
 2. The method of claim 1, wherein each of the dummy padsis arranged in a middle area of the respective die pad groups.
 3. Themethod of claim 2, wherein the inner leads and the connecting portionswhich are separated by the dummy pads are punched simultaneously.